The invention relates in general to the field of microfluidic devices. It further concerns verification and/or security features for such devices, as well as methods for optically reading, decoding and encoding such features in microfluidic devices. In embodiments, such methods are applied to test devices for diagnostic testing, such as rapid testing devices (e.g., point-of-care test devices and over-the-counter tests).
Microfluidics deals with the precise control and manipulation of small volumes of fluids that are typically constrained to micro scale channels and to volumes typically in the sub-millimeter range. Prominent features of microfluidics originate from the peculiar behavior that liquids exhibit at the micro scale. Flow of liquids in microfluidics is typically laminar. Volumes well below one nanoliter can be reached by fabricating structures with lateral dimensions in the micrometer range. Microfluidic devices generally refer to microfabricated devices, which are used for pumping, sampling, mixing, analyzing and dosing liquids.
Many microfluidic devices have user chip interfaces and closed flow paths. Closed flow paths facilitate the integration of functional elements (e.g., heaters, mixers, pumps, UV detectors, valves, etc.) into one device while minimizing problems related to, e.g., leaks and evaporation. The analysis of liquid samples often requires a series of steps (e.g., filtration, dissolution of reagents, heating, washing, reading of signal, etc.).
Rapid diagnostic test (RDT) devices are devices used for quick and easy medical diagnostic tests. They typically allow results to be obtained within a few hours or less. They notably include point-of-care (POC) test devices and over-the-counter (OTC) tests.
Point-of-care (POC) test devices are devices used for point-of-care testing, also called bedside testing. Such devices allow medical diagnostic testing at or near the point of care, e.g., at the time and place of the patient care. Over-the-counter (OTC) tests are similar devices. They are, however, typically simpler than POC devices and can often be purchased in pharmacies for people to perform the test themselves, e.g., at home or away from healthcare settings and without assistance from healthcare staff.
Such test devices are typically portable, e.g., handheld devices, are easy to use, are of low cost to manufacture, and fast. They are therefore considered an essential technology by the World Health Organization (WHO) for combatting infectious diseases, amongst other types of diseases, and for improving health in countries where such diseases are endemic. OTC devices are frequently used, e.g., for monitoring therapy (e.g., to ensure appropriate doses of blood anticoagulant drugs), for monitoring glucose in blood, or for detecting drugs of abuse in body fluids.
The most widely used diagnostic devices are perhaps the so-called “lateral flow assays”, which rely on a stripe of cellulose along which a sample flows and reacts with reagents present on the stripe. Such devices are also called strip tests and are typically provided in the form of sticks to be dipped into a liquid to perform the test. If analytes are present in the sample, a visual cue such as a colored signal appears on the stripe. Similar test devices are used to detect malaria, hepatitis virus, HIV, biomarkers related to heart failure, etc.
Besides diseases, test devices as contemplated herein are commonly used to detect a specific condition, such as pregnancy or ovulation.
There has been numerous reports and alerts regarding such tests being counterfeited or inappropriately sold. For instance, several sources have reported that counterfeited tests had been sold for diagnosing Leishmaniasis. In addition, fake pregnancy tests, fake tests for glucose monitoring and fake human immunodeficiency virus (HIV) test kits (originally designed to test for pregnancy or other conditions) have reportedly been sold, amongst other frauds.
The WHO believes that the counterfeiting of tests compromises the surveillance, detection, and eradication of some diseases. This is particularly worrying with respect to large-scale infectious diseases, as the prevention, treatment, detection, and eradication of some diseases typically needs concerted and global surveillance. Typically, programs for the surveillance, detection, and eradication of some diseases involve heterogeneous types of patients and healthcare settings (e.g., itinerant outpost vs. hospital). A task force called IMPACT (http://apps.who.int/impact/en/) has therefore been setup to provide recommendation and raise awareness regarding the problem of counterfeiting of medical products. This task force focuses on counterfeited drugs and gives useful recommendations on common approaches for adding security features to medical product packages.
Unfortunately, such security features are frequently breached in practice.